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  • 1.
    Blom, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Photoswitchable peptidomimetics with a stiff-stilbene chromophore for inhibition of Mycobacterium tuberculosis RNRManuscript (preprint) (Other academic)
    Abstract [en]

    Peptidomimetics incorporating two amino acids 1 and 2 with a stiff stilbene chromophore have been screened by a computational study and compared to a previously investigated analog 3 with stilbene chromophore. The effect of E-Z isomerization of the chromophores on the conformational properties of the petidomimetics was assessed via the frequency of hydrogen bonding between the two peptide strands attached to either side of the chromophore. Substantial differences between the three amino acids were thus indicated, in line with the anticipated effect of chromophore rigidity variation.

  • 2.
    Blom, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Synthesis and characterization of photoswitchable stiff-stilbene based amino acid derivativesManuscript (preprint) (Other academic)
    Abstract [en]

    Synthetic routes towards the Boc-protected amino acids 1 and 2 incorporating the stiff stilbene chromophore via the corresponding indanone carboxylic acids have been devised. Crucial steps are a reductive McMurry coupling of the indanone carboxylic acids, yielding stiff stilbene dicarboxylic acid esters. Hydrolysis to the monoester and conversion to the azides, followed by a Curtius rearrangement afforded the Boc-protected amino acid ester 1.

  • 3.
    Blom, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Norrehed, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Claes-Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Huang, Hao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Light, Mark E.
    Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, U.K.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Synthesis and Properties of Bis-Porphyrin Molecular Tweezers: Effects of Spacer Flexibility on Binding and Supramolecular Chirogenesis2016In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 21, no 1Article in journal (Refereed)
    Abstract [en]

    Abstract: Ditopic binding of various dinitrogen compounds to three bisporphyrin molecular tweezers with spacers of varying conformational rigidity, incorporating the planar ene-diyne (1), the helical stiff stilbene (2), or the semirigid glycoluril motif fused to  the porphyrins (3) are compared. Binding constants Ka = 10^4 to 10^6 M^-1 reveal subtle  differences between these tweezers, that are discussed in terms of porphyrin dislocation  modes. Exciton coupled circular dichroism (ECCD) of complexes with chiral dinitrogen  guests provides experimental evidence for the conformational properties of the tweezers. The results are further supported and rationalized by conformational analysis.

  • 4.
    Blom, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Olsson, Sandra
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Norrehed, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Claes-Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Photomodulable bis-porphyrin molecular tweezers as dynamic host systems for diamine guestsManuscript (preprint) (Other academic)
    Abstract [en]

    Bisporphyrin molecular tweezers with an enediyne (1) or a stiff stilbene (2) photoswitchable spacer are proposed as systems for modulation of bitopic binding to diamine guests via E/Z photoisomerization. The photoisomerization has been monitored by UV-Vis and 1H NMR spectroscopy and occurs without side reactions such as Bergman cyclization. Possible applications are rationalized in terms of competitive binding involving monoamine/diamine mixtures, and are supported by conformational analysis of the envisioned host-guest complexes. Binding dynamics for conformationally flexible guests show significantly different performance of aliphatic 1,w-diamine guests with varying N-N distance.

  • 5.
    Cadu, Alban
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Iridium Catalysed Asymmetric Hydrogenation of Pyridines2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents the hydrogenation of substituted pyridines using N,P-ligated iridium catalystsin homogeneous media. These iridium catalysts were developed within this research group in thepast decade. This method of hydrogenation is highly stereoselective, and in several cases good to excellent ees were obtained.The hydrogenation of substituted pyridines was studied: by screening for the catalyst giving thehighest conversion and ee, by optimising the reaction conditions and by attempting to improve existingcatalysts. New substrates were synthesised for this process, in particular alkyl substituted Nprotectedpyridines. Their reduction provided chiral piperidines, which could be used as chiralbuilding blocks once deprotected.

    List of papers
    1. Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines
    Open this publication in new window or tab >>Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines
    2013 (English)In: Asian Journal of Organic Chemistry, ISSN 2193-5807, Vol. 2, no 12, p. 1061-1065Article in journal (Refereed) Published
    Abstract [en]

    Asymmetric hydrogenation of ortho-substituted pyridines catalyzed by N,P-ligated iridium is demonstrated. To facilitate this reaction, the aromaticity of the pyridines was weakened by forming N-iminopyridium ylides. The reactions give very high conversions, and after a single recrystallization, excellent ee of up to 98 % was obtained. This method lends itself to the synthesis of chiral piperidine building blocks.

    Keywords
    hydrogenation, iridium, N-iminopyridium ylides, pyridines, selective catalysis
    National Category
    Organic Chemistry Inorganic Chemistry
    Research subject
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-212412 (URN)10.1002/ajoc.201300160 (DOI)000328218000008 ()
    Available from: 2013-12-10 Created: 2013-12-10 Last updated: 2017-01-25Bibliographically approved
  • 6.
    Cadu, Alban
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Noble Metal Catalysed Reductions and Rearrangements2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The focus of this thesis has been organometallic catalysis applied to compounds containing heteroatoms which are usually poisonous to metal catalysts, by channelling their innate reactivity advantageously. The studies described in this thesis concentrate, in the first part, on iridium catalysed asymmetric hydrogenation (papers I and II) and in the second part, on gold catalysed internal rearrangements (papers III and IV). In each case, two classes of compounds are studied: pyridinium salts or sulphurous compounds. The asymmetric hydrogenation of pyridinium compounds was performed with 2% loading of N,P-ligated Ir catalyst with I2 additive (paper I) to achieve moderate to good enantiomeric excess (up to 98%). In paper II, olefinic sulphones were hydrogenated with an efficient 0.5% catalytic loading. In most cases full conversion was obtained and with good to excellent ees (up to 99%). The products of these reductions are chiral compounds, which could constitute further chemical building blocks. Palladium and gold were used sequentially in paper III, in order to perform a “Click” thiol-yne reaction followed by a semi-Pinacol rearrangement, leading to isolated yields of up to 98%. In paper IV The gold catalysed rearrangement of alkyl-pyridinium diynes was conducted, with a number of substrates providing >90% NMR yield. A highly selective hydrogenation was performed with a heterogeneous palladium catalyst to yield single diastereomer products. This methodology consists of up to three steps, with two catalysts in one pot.

    List of papers
    1. Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines
    Open this publication in new window or tab >>Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines
    2013 (English)In: Asian Journal of Organic Chemistry, ISSN 2193-5807, Vol. 2, no 12, p. 1061-1065Article in journal (Refereed) Published
    Abstract [en]

    Asymmetric hydrogenation of ortho-substituted pyridines catalyzed by N,P-ligated iridium is demonstrated. To facilitate this reaction, the aromaticity of the pyridines was weakened by forming N-iminopyridium ylides. The reactions give very high conversions, and after a single recrystallization, excellent ee of up to 98 % was obtained. This method lends itself to the synthesis of chiral piperidine building blocks.

    Keywords
    hydrogenation, iridium, N-iminopyridium ylides, pyridines, selective catalysis
    National Category
    Organic Chemistry Inorganic Chemistry
    Research subject
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-212412 (URN)10.1002/ajoc.201300160 (DOI)000328218000008 ()
    Available from: 2013-12-10 Created: 2013-12-10 Last updated: 2017-01-25Bibliographically approved
    2. An Enantioselective Approach to the Preparation of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation
    Open this publication in new window or tab >>An Enantioselective Approach to the Preparation of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation
    Show others...
    2014 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 136, no 47, p. 16557-16562Article in journal (Refereed) Published
    Abstract [en]

    Several chiral sulfonyl compounds were prepared using the iridium catalyzed asymmetric hydrogenation reaction. Vinylic, allylic and homoallylic sulfone substitutions were investigated, and high enantioselectivity is maintained regardless of the location of the olefin with respect to the sulfone. Impressive stereoselectivity was obtained for dialkyl substitutions, which typically are challenging substrates in the hydrogenation. As expected, the more bulky Z-substrates were hydrogenated slower than the corresponding E isomers, and in slightly lower enantioselectivity.

    Place, publisher, year, edition, pages
    American Chemical Society (ACS), 2014
    National Category
    Organic Chemistry
    Research subject
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-236862 (URN)10.1021/ja5079877 (DOI)000345720500016 ()25300238 (PubMedID)
    Available from: 2014-11-24 Created: 2014-11-24 Last updated: 2017-12-05Bibliographically approved
    3. One-Pot Synthesis of Keto Thioethers by Palladium/Gold-Catalyzed Click and Pinacol Reactions
    Open this publication in new window or tab >>One-Pot Synthesis of Keto Thioethers by Palladium/Gold-Catalyzed Click and Pinacol Reactions
    Show others...
    2014 (English)In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 16, no 21, p. 5556-5559Article in journal (Refereed) Published
    Abstract [en]

    An atom-efficient synthesis of keto thioethers was devised via tandem gold/palladium catalysis. The reaction proceeds through a regioselective thiol attack at the β-position of the alcohol, followed by an alkyl, aryl, or benzyl 1,2-shift. Both acyclic and cyclic systems were studied, in the latter case leading to the ring expansion of cyclic substrates.

    Place, publisher, year, edition, pages
    American Chemical Society (ACS), 2014
    Keywords
    Gold, Palladium, thioether, catalysis, synthesis
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-236857 (URN)10.1021/ol502553p (DOI)000344635200013 ()25325145 (PubMedID)
    Available from: 2014-11-24 Created: 2014-11-24 Last updated: 2017-12-05Bibliographically approved
    4. Dual Gold (I) Catalysed Cyclisation of Dialkynyl Pyridinium salts
    Open this publication in new window or tab >>Dual Gold (I) Catalysed Cyclisation of Dialkynyl Pyridinium salts
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Novel dialkynyl pyridines were synthesised and protected as alkyl salts for dual gold (I) catalysed cycloisomerisation. Different alkyl groups and counter ions were screened for the salts, with benzyl and PF6- providing the best results. The cyclisation led to NMR yields of >95% being obtained for a number of substrates. Step-wise hydrogenation of products could be carried out in one-pot by Pd/C, with selective reduction of the double bonds, followed by deprotection of the Bn group.

    Keywords
    chemistry
    National Category
    Organic Chemistry
    Research subject
    Chemistry with specialization in Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-272369 (URN)
    Available from: 2016-01-13 Created: 2016-01-13 Last updated: 2016-02-12Bibliographically approved
  • 7.
    Cadu, Alban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Pher G.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Development of iridium-catalyzed asymmetric hydrogenation: New catalysts, new substrate scope2012In: Journal of Organometallic Chemistry, ISSN 0022-328X, E-ISSN 1872-8561, Vol. 714, p. 3-11Article, review/survey (Refereed)
    Abstract [en]

    A review. The asym. hydrogenation of olefins is a tremendously powerful tool used to synthesize chiral mols. The field was pioneered using rhodium- and ruthenium- based catalysts; however, catalysts based on both of these metals suffer from limitations, such as the need for directing substituents near or even adjacent to the olefin. Iridium-based catalysts do not suffer from this flaw and can thus hydrogenate a wide variety of olefins, including some tetra substituted ones. It is also possible for iridium-based catalysts to hydrogenate hetero-π bonds such as those found in heteroarom. rings. This review summarizes the contributions made to this field by the authors in the past few years. [on SciFinder(R)]

  • 8.
    Cadu, Alban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Pher G
    Iridium catalysis: Application of asymmetric reductive hydrogenation2013In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 42, no 40, p. 14345-14356Article in journal (Refereed)
    Abstract [en]

    Iridium, despite being one of the least abundant transition metals, has found several uses. N,P-ligated iridium catalysts are used to perform many highly selective reactions. These methodologies have been developed extensively over the past 15 years. More recently, the application of iridium N,P catalysts in asymmetric hydrogenation has been a focus of research to find novel applications and to expand on their current synthetic utility. The aim of this perspective is to highlight the advances made by the Andersson group.

  • 9.
    Cadu, Alban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Upadhyay, Puspesh K.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Andersson, Pher G.
    Stockholm University.
    Iridium-Catalyzed Asymmetric Hydrogenation of Substituted Pyridines2013In: Asian Journal of Organic Chemistry, ISSN 2193-5807, Vol. 2, no 12, p. 1061-1065Article in journal (Refereed)
    Abstract [en]

    Asymmetric hydrogenation of ortho-substituted pyridines catalyzed by N,P-ligated iridium is demonstrated. To facilitate this reaction, the aromaticity of the pyridines was weakened by forming N-iminopyridium ylides. The reactions give very high conversions, and after a single recrystallization, excellent ee of up to 98 % was obtained. This method lends itself to the synthesis of chiral piperidine building blocks.

  • 10.
    Cadu, Alban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Watile, Rahul
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Biswas, Srijit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Sjöberg, Per J
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Samec, Joseph
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    One-Pot Synthesis of Keto Thioethers by Palladium/Gold-Catalyzed Click and Pinacol Reactions2014In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 16, no 21, p. 5556-5559Article in journal (Refereed)
    Abstract [en]

    An atom-efficient synthesis of keto thioethers was devised via tandem gold/palladium catalysis. The reaction proceeds through a regioselective thiol attack at the β-position of the alcohol, followed by an alkyl, aryl, or benzyl 1,2-shift. Both acyclic and cyclic systems were studied, in the latter case leading to the ring expansion of cyclic substrates.

  • 11.
    Dinér, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Superacid-Promoted Ionization of Alkanes Without Carbonium Ion Formation: A Density Functional Theory Study2012In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 116, no 40, p. 9979-9984Article in journal (Refereed)
    Abstract [en]

    The carbonium ion has been suggested to be the intermediate in superacid-promoted reactions (SbF5-HF) such as hydrogen-deuterium exchange and in the electrophilic C-H cleavage into hydrogen and the carbenium ion. In this study, the superacid-promoted C-H cleavage into hydrogen and the carbenium ion was studied using density functional theory (B3LYP and M062X) and ab initio methods (MP2 and CCSD). The calculations suggest that the superacid-promoted C-H cleavage proceeds via a concerted transition state leading to hydrogen (H-2) and the carbenium ion without the formation of the elusive carbonium ion. The reactivity for the superacid promoted C-H cleavage decreases upon going from isobutane (tertiary) > propane (secondary) > isobutane (primary) > propane (primary) > ethane >> methane.

  • 12.
    Galkin, Maxim
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Palladium-catalyzed lignin valorization: Towards a lignin-based biorefinery2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The work described in this thesis focuses on the cleavage of the β-O-4′ bond, which is the most abundant interunit linkage in the lignin polymer.

    In the first part, three methods based on palladium catalysis have been developed and their applicability has been verified using lignin model compounds. A transfer hydrogenolysis of the β-O-4′ bond using formic acid as a mild hydrogen donor together with a base. An aerobic oxidation of the benzylic alcohol motif in the β-O-4′ linkage to generate a key intermediate in the cleavage reaction was performed. A redox neutral cleavage of the β-O-4′ bond was accomplished in which no stoichiometric reducing or oxidizing agents were added.

    In the second part of the thesis, a mechanistic study is presented. The corresponding ketone from a dehydrogenation reaction of the benzylic alcohol motif was identified to be the key intermediate. This ketone and its enol tautomer was found to be responsible for the β-O-4′ bond cleavage reaction under the employed reaction conditions.

    In the final part of this thesis, the methodologies have been applied to native lignin. The depolymerization reaction was combined with organosolv pulping. This approach was successful, and together with cellulose and hemicellulose, propenyl aryls were generated in excellent yields directly from wood. In this transformation, the lignin derived molecules have been reduced by an endogenous hydrogen donor from the wood.

    List of papers
    1. Mild Heterogeneous Palladium-Catalyzed Cleavage of beta-O-4 '-Ether Linkages of Lignin Model Compounds and Native Lignin in Air
    Open this publication in new window or tab >>Mild Heterogeneous Palladium-Catalyzed Cleavage of beta-O-4 '-Ether Linkages of Lignin Model Compounds and Native Lignin in Air
    Show others...
    2014 (English)In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 6, no 1, p. 179-184Article in journal (Refereed) Published
    Abstract [en]

    A mild and robust heterogeneous palladium-catalyzed CO bond cleavage of 2-aryloxy-1-arylethanols using formic acid as reducing agent in air was developed. The cleaved products were isolated in 92-98% yield; and by slightly varying the reaction conditions, a ketone, an alcohol, or an alkane can be generated in near-quantitative yield. This reaction is applicable to cleaving the -O-4-ether bond found in lignin polymers of different origin. The reaction was performed on a lignin polymer model to generate either the monomeric aryl ketone or alkane in a quantitative yield. Moderate depolymerization was achieved with native lignin at similar reaction conditions. Mechanistic studies under kinetic control indicate that an initial palladium-catalyzed dehydrogenation of the alcohol is followed by insertion of palladium to an enol equivalent. A palladium-formato complex reductively cleaves the palladium-enolate complex to generate the ketone.

    Keywords
    heterogeneous catalysis, cleavage reactions, green chemistry, palladium, polymers, lignin
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-220309 (URN)10.1002/cctc.201300540 (DOI)000330636800023 ()
    Note

    De två första författarna delar första författarskapet.

    Available from: 2014-03-17 Created: 2014-03-12 Last updated: 2017-12-05Bibliographically approved
    2. Selective Aerobic Benzylic Alcohol Oxidation of Lignin Model Compounds: Route to Aryl Ketones
    Open this publication in new window or tab >>Selective Aerobic Benzylic Alcohol Oxidation of Lignin Model Compounds: Route to Aryl Ketones
    2015 (English)In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 7, no 3, p. 401-404Article in journal (Refereed) Published
    Abstract [en]

    A mild and chemoselective oxidation of the -alcohol in -O-4-ethanoaryl and -O-4-glycerolaryl ethers has been developed. The benzylic alcohols were selectively dehydrogenated to the corresponding ketones in 60-93% yield. A one-pot selective route to aryl ethyl ketones was performed. The catalytic system comprises recyclable heterogeneous palladium, mild reaction conditions, green solvents, and oxygen in air as oxidant. Catalytic amounts of a coordinating polyol were found pivotal for an efficient aerobic oxidation.

    Keywords
    biomass valorization, heterogeneous catalysis, lignin, oxidation, palladium
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-246820 (URN)10.1002/cctc.201402825 (DOI)000349147100005 ()
    Available from: 2015-03-11 Created: 2015-03-10 Last updated: 2017-12-04Bibliographically approved
    3. Mild and Robust Redox-Neutral Pd/C-Catalyzed Lignol -O-4 Bond Cleavage Through a Low-Energy-Barrier Pathway
    Open this publication in new window or tab >>Mild and Robust Redox-Neutral Pd/C-Catalyzed Lignol -O-4 Bond Cleavage Through a Low-Energy-Barrier Pathway
    2015 (English)In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, no 13, p. 2187-2192Article in journal (Refereed) Published
    Abstract [en]

    A Pd/C catalyzed redox neutral CO bond cleavage of 2-aryloxy-1-arylethanols has been developed. The reactions are carried out at 80 degrees C, in air, using a green solvent system to yield the aryl ketones in near quantitative yields. Addition of catalytic amounts of a hydrogen source to the reaction mixture activates the catalyst to proceed through a low energy barrier pathway. Initial studies support a transfer hydrogenolysis reaction mechanism that proceeds through an initial dehydrogenation followed by an enol adsorption to Pd/C and a reductive CO bond cleavage.

    Keywords
    heterogeneous catalysis, lignin, palladium, reaction mechanisms, transfer hydrogenolysis
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-259649 (URN)10.1002/cssc.201500117 (DOI)000357619000004 ()25925736 (PubMedID)
    Funder
    Swedish Energy Agency
    Available from: 2015-08-20 Created: 2015-08-10 Last updated: 2017-12-04Bibliographically approved
    4. Selective Route to 2-Propenyl Aryls Directly from Wood by a Tandem Organosolv and Palladium-Catalysed Transfer Hydrogenolysis
    Open this publication in new window or tab >>Selective Route to 2-Propenyl Aryls Directly from Wood by a Tandem Organosolv and Palladium-Catalysed Transfer Hydrogenolysis
    2014 (English)In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 8, p. 2154-2158Article in journal (Refereed) Published
    Abstract [en]

    A tandem organosolv pulping and Pd-catalysed transfer hydrogenolysis depolymerisation and deoxygenation has been developed. The tandem process generated 2-methoxy-4-(prop-1-enyl)phenol in 23 % yield (92 % theoretical monomer yield) starting from pine wood and 2,6-dimethoxy-4-(prop-1-enyl)phenol in 49 % yield (92 % theoretical monomer yield) starting from birch wood. Only endogenous hydrogen from wood was consumed, and the reaction was performed using green solvents.

    Keywords
    Biomass, Lignin Green, Chemistry, Palladium, catalysis
    National Category
    Organic Chemistry
    Research subject
    Chemistry with specialization in Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-226637 (URN)10.1002/cssc.201402017 (DOI)000340519500016 ()
    Funder
    Swedish Energy Agency
    Available from: 2014-06-18 Created: 2014-06-18 Last updated: 2017-12-05Bibliographically approved
  • 13.
    Galkin, Maxim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Samec, Joseph
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Selective Route to 2-Propenyl Aryls Directly from Wood by a Tandem Organosolv and Palladium-Catalysed Transfer Hydrogenolysis2014In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 8, p. 2154-2158Article in journal (Refereed)
    Abstract [en]

    A tandem organosolv pulping and Pd-catalysed transfer hydrogenolysis depolymerisation and deoxygenation has been developed. The tandem process generated 2-methoxy-4-(prop-1-enyl)phenol in 23 % yield (92 % theoretical monomer yield) starting from pine wood and 2,6-dimethoxy-4-(prop-1-enyl)phenol in 49 % yield (92 % theoretical monomer yield) starting from birch wood. Only endogenous hydrogen from wood was consumed, and the reaction was performed using green solvents.

  • 14.
    Gustafsson, Tomas
    et al.
    Karolinska Inst, Div Biochem, Dept Med Biochem & Biophys, Scheeles Vag 2, SE-17177 Stockholm, Sweden.; Umea Univ, Sunderby Res Unit, Dept Clin Microbiol, Clin Bacteriol, Umea, Sweden.
    Osman, Harer
    Karolinska Inst, Div Biochem, Dept Med Biochem & Biophys, Scheeles Vag 2, SE-17177 Stockholm, Sweden.
    Werngren, Jim
    Publ Hlth Agcy Sweden, Dept Microbiol, Solna, Sweden.
    Hoffner, Sven
    Publ Hlth Agcy Sweden, Dept Microbiol, Solna, Sweden.
    Engman, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Holmgren, Arne
    Karolinska Inst, Div Biochem, Dept Med Biochem & Biophys, Scheeles Vag 2, SE-17177 Stockholm, Sweden.
    Ebselen and analogs as inhibitors of Bacillus anthracis thioredoxin reductase and bactericidal antibacterials targeting Bacillus species, Staphylococcus aureus and Mycobacterium tuberculosis2016In: Biochimica et Biophysica Acta - General Subjects, ISSN 0304-4165, E-ISSN 1872-8006, Vol. 1860, no 6, p. 1265-1271Article in journal (Refereed)
    Abstract [en]

    Background: Bacillus anthracis is the causative agent of anthrax, a disease associated with a very high mortality rate in its invasive forms.

    Methods: We studied a number of ebselen analogs as inhibitors of B. anthracis thioredoxin reductase and their antibacterial activity on Bacillus subtilis, Staphylococcus aureus, Bacillus cereus and Mycobacterium tuberculosis.

    Results: The most potent compounds in the series gave IC50 values down to 70 nM for the pure enzyme and minimal inhibitory concentrations (MICs) down to 0.4 mu M (0.12 mu g/ml) for B. subtilis,1.5 mu M (0.64 mu g/ml) for S. aureus, 2 mu M (0.86 mu g/ml) for B. cereus and 10 mu g/ml for M. tuberculosis. Minimal bactericidal concentrations (MBCs) were found at 1-1.5 times the MIC, indicating a general, class-dependent, bactericidal mode of action. The combined bacteriological and enzymological data were used to construct a preliminary structure-activity-relationship for the benzoisoselenazol class of compounds. When S. aureus and B. subtilis were exposed to ebselen, we were unable to isolate resistant mutants on both solid and in liquid medium suggesting a high resistance barrier.

    Conclusions: These results suggest that ebselen and analogs thereof could be developed into a novel antibiotic class, useful for the treatment of infections caused by B. anthracis, S. aureus, M. tuberculosis and other clinically important bacteria. Furthermore, the high barrier against resistance development is encouraging for further drug development.

    General significance: We have characterized the thioredoxin system from B. anthracis as a novel drug target and ebselen and analogs thereof as a potential new class of antibiotics targeting several important human pathogens.

  • 15.
    Huang, Hao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Karlsson, Christoffer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Sjödin, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Hydroquinone–pyrrole dyads with varied linkers2016In: Beilstein Journal of Organic Chemistry, ISSN 2195-951X, E-ISSN 1860-5397, Vol. 12, p. 89-96Article in journal (Refereed)
    Abstract [en]

    A series of pyrroles functionalized in the 3-position with p-dimethoxybenzene via various linkers (CH2, CH2CH2, CH=CH, C≡C) has been synthesized. Their electronic properties have been deduced from 1H NMR, 13C NMR, and UV–vis spectra to detect possible interactions between the two aromatic subunits. The extent of conjugation between the subunits is largely controlled by the nature of the linker, with the largest conjugation found with the trans-ethene linker and the weakest with the aliphatic linkers. DFT calculations revealed substantial changes in the HOMO–LUMO gap that correlated with the extent of conjugation found experimentally. The results of this work are expected to open up for use of the investigated compounds as components of redox-active materials in sustainable, organic electrical energy storage devices.

  • 16.
    Karlsson, Christoffer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Blom, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Johansson, Miranda
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Jansson, Anna M.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Scifo, Enzo
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Karlén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Govender, Thavendran
    Catalysis and Peptide Research Unit, University of KwaZulu Natal, South Africa.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Phototriggerable peptidomimetics for the inhibition of Mycobacterium turberculosis ribonucleotide reductase by targeting protein-protein binding2015In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 13, no 9, p. 2612-2621Article in journal (Refereed)
    Abstract [en]

    Incorporation of an artificial amino acid 2 with a stilbene chromophore into peptidomimetics with three to nine amino acids yields phototriggerable candidates for inhibition of the binding between the R1 and R2 subunits of the M. tuberculosis ribonucleotide reductase (RNR). Interstrand hydrogen bond probability was used as a guideline for predicting conformational preferences of the photoisomers. Binding of these inhibitors has been rationalized by docking studies with the R1 unit. Significant differences in binding of the photoisomers were observed. For the shorter peptidomimetics, stronger binding of the Z isomer might indicate hydrophobic interactions between the stilbene chromophore and the binding site.

  • 17.
    Kirchhain, Arno
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Yu, Wenbin
    Engman, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Organochalcogen stabilizers efficiently protect model polyolefins exposed to chlorinated media2015In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 118, p. 82-87Article in journal (Refereed)
    Abstract [en]

    The small amounts of chlorine dioxide that are routinely supplemented to drinking water as a disinfectant also cause a degradation of the polyolefin pipes that are used for distribution of the water. Commonly used phenolic antioxidants can extend the service life of the polymer but the expected lifetime is still much shorter than desired (50 years) due to depletion of the antioxidant in the surface zone exposed to the aqueous solution. In search for better stabilizers for the pipes, we have tested an organotellurium compound, 4-(N,N-dimethylamino)phenyl 3-phenoxypropyl telluride (1), as well as its corresponding selenium and sulphur analogues and a series of organotellurium compounds where the electron density at the heteroatom was varied. Stabilizers were dissolved in squalane, which is a liquid hydrocarbon that could serve as a model for a polyolefin. The oxidation induction time (OIT), determined after exposure of the squalane solution to an aqueous solution of 10 ppm of chlorine dioxide for various times was determined by DSC to indicate the loss of antioxidant protection. Whereas Irganox 1010 was only effective as a stabilizer for a few hours, many of the organochalcogen compounds were considerably more resistant (>91 h for compound 1) towards chlorine dioxide.

    Thermogravimetric analyses of antioxidants indicated insignificant decomposition below 200 °C and increasing stability for the lighter chalcogen compounds (telluride < selenide < sulfide). Among organotelluriums, stability increases with increasing electron density at the heteroatom. Oxidation potentials of stabilizers as determined by cyclic voltammetry correlated fairly well with their protective effect in squalane (OIT-values). We therefore hypothesize that these compounds act primarily as electron donors towards peroxyl radicals. As determined by 125Te NMR-spectroscopy, organotellurium compound 1 in the presence of an excess of chlorine dioxide failed to produce an oxidation product. This may be the clue to its long-lasting protective effect in the squalane-assay.

  • 18.
    Li, Jia-Qi
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Studies of Hydrogenations and Isomerizations of Olefins and Alkylations of Amines Using Iridium Catalysts2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis describes three types of reactions that were carried out using iridium catalysts.

    The first type is the iridium-catalyzed asymmetric hydrogenation of olefins. In paper I, the preparation of a new type of bicyclic thiazole-phosphine based iridium complex was described. The new catalysts have displayed high activity and enantioselectivity in the asymmetric hydrogenation of unfunctionalized olefins. Papers II and III focus on the expansion of the substrate scope for the iridium catalyzed asymmetric hydrogenation in which a number of heterocyclic olefins were evaluated. In paper IV, the enantioselective asymmetric hydrogenation of α, β-unsaturated esters was described. The chiral products bearing tertiary stereogenic centers obtained by hydrogenation have great synthetic value and have been used in the synthesis of pharmaceuticals as well as in the total synthesis of natural products.

    The second type is the asymmetric isomerization of allylic alcohols. In paper V, both cis and trans primary allylic alcohols were isomerized to the corresponding β-chiral aldehydes in high enantioselectivities by an N,P-chelating iridium complex.

    The third type is the selective mono-N-alkylation of amines with alcohols. In paper VI, a phosphine/NHC based iridium catalyst was synthesized and applied in the alkylation of amines. It is the first time that this type of transformation is carried out at room temperature.

    List of papers
    1. Bicyclic phosphine-thiazole ligands for the asymmetric hydrogenation of olefins
    Open this publication in new window or tab >>Bicyclic phosphine-thiazole ligands for the asymmetric hydrogenation of olefins
    2010 (English)In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 21, no 11-12, p. 1328-1333Article in journal (Refereed) Published
    Abstract [en]

    New bicyclic thiazole-based chiral N,P-chelating ligands were developed. High activities and enantioselectivities were achieved in the iridium-catalyzed asymmetric hydrogenation of olefins with the new ligands.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-135190 (URN)10.1016/j.tetasy.2010.03.023 (DOI)000281095300002 ()
    Available from: 2010-12-06 Created: 2010-12-06 Last updated: 2017-12-11Bibliographically approved
    2. Highly Flexible Synthesis of Chiral Azacycles via Iridium-Catalyzed Hydrogenation
    Open this publication in new window or tab >>Highly Flexible Synthesis of Chiral Azacycles via Iridium-Catalyzed Hydrogenation
    Show others...
    2010 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, no 26, p. 8880-8881Article in journal (Refereed) Published
    Abstract [en]

    A range of saturated chiral azacycles has been prepared in high yield and with high selectivity from simple starting materials. A modular approach with ring-closing metathesis as a key step was used to produce a number of five-, six-, and seven-membered cyclic alkenes. Asymmetric hydrogenation catalyzed by N,P-ligated iridium complexes gave saturated azacycles in high optical purity. This methodology was demonstrated in the synthesis of a pharmaceutical precursor.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-135809 (URN)10.1021/ja103901e (DOI)000279561200033 ()20557052 (PubMedID)
    Available from: 2010-12-09 Created: 2010-12-08 Last updated: 2017-12-11Bibliographically approved
    3. Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
    Open this publication in new window or tab >>Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
    Show others...
    2012 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 21, p. 6507-6513Article in journal (Refereed) Published
    Abstract [en]

    Several types of chiral hetero- and carbocyclic compounds have been synthesized by using the asymmetric hydrogenation of cyclic alkenes. N,P-Ligated iridium catalysts reduced six-membered cyclic alkenes with various substituents and heterofunctionality in good to excellent enantioselectivity, whereas the reduction of five-membered cyclic alkenes was generally less selective, giving modest enantiomeric excesses. The stereoselectivity of the hydrogenation depended more strongly on the substrate structure for the five- rather than the six-membered cyclic alkenes. The major enantiomer formed in the reduction of six-membered alkenes could be predicted from a selectivity model and isomeric alkenes had complementary enantioselectivity, giving opposite optical isomers upon hydrogenation. The utility of the reaction was demonstrated by using it as a key step in the preparation of chiral 1,3-cis-cyclohexane carboxylates.

    Keywords
    asymmetric synthesis, heterocyclic compounds, homogeneous catalysis, hydrogenation, iridium
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-175620 (URN)10.1002/chem.201104073 (DOI)000304045000016 ()
    Available from: 2012-06-12 Created: 2012-06-11 Last updated: 2017-12-07Bibliographically approved
    4. Highly Enantioselective Asymmetric Isomerization of Primary Allylic Alcohols with an Iridium-N,P Complex
    Open this publication in new window or tab >>Highly Enantioselective Asymmetric Isomerization of Primary Allylic Alcohols with an Iridium-N,P Complex
    2011 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 17, no 40, p. 11143-11145Article in journal (Refereed) Published
    Keywords
    aldehydes, allylic alcohols, asymmetric catalysis, iridium, isomerization, N, P ligands
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-164577 (URN)10.1002/chem.201101524 (DOI)000297013100011 ()
    Available from: 2011-12-21 Created: 2011-12-21 Last updated: 2017-12-08Bibliographically approved
    5. Highly Enantioselective Iridium-Catalyzed Hydrogenation of α,β-Unsaturated Esters
    Open this publication in new window or tab >>Highly Enantioselective Iridium-Catalyzed Hydrogenation of α,β-Unsaturated Esters
    2012 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 34, p. 10609-10616Article in journal (Refereed) Published
    Abstract [en]

    α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals.

    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-182641 (URN)10.1002/chem.201200907 (DOI)000307387300020 ()22807347 (PubMedID)
    Available from: 2012-10-14 Created: 2012-10-14 Last updated: 2017-12-07Bibliographically approved
    6. Room Temperature and Solvent-Free Iridium-Catalyzed  Alkylation of Amines with Alcohols
    Open this publication in new window or tab >>Room Temperature and Solvent-Free Iridium-Catalyzed  Alkylation of Amines with Alcohols
    (English)Manuscript (preprint) (Other academic)
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-182645 (URN)
    Available from: 2012-10-16 Created: 2012-10-14 Last updated: 2012-11-12
  • 19.
    Li, Jia-Qi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Room Temperature and Solvent-Free Iridium-Catalyzed  Alkylation of Amines with AlcoholsManuscript (preprint) (Other academic)
  • 20.
    Li, Jia-Qi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Xu, Quan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Highly Enantioselective Iridium-Catalyzed Hydrogenation of α,β-Unsaturated Esters2012In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 34, p. 10609-10616Article in journal (Refereed)
    Abstract [en]

    α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals.

  • 21.
    Mesas Sánchez, Laura
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Organocatalytic Acylation for the Kinetic Resolution of Secondary Aryl Alcohols: Synthetic Applications and Mechanistic Studies2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The research described in this thesis focuses on the catalytic acylative kinetic resolution (KR) of aromatic secondary alcohols, using a planar-chiral 4-(dimethylamino)pyridine (DMAP) organocatalyst.

    In the first part of this thesis, the substrate scope of the above mentioned process was expanded to aromatic secondary alcohols that contain an extra functional group in the alkyl moiety, such as 1,2-azido alcohols, 2-hydroxy-2-aryl-ethylphosphonates and 2-hydroxy-2-aryl esters. Thus, the preparation of highly functionalized compounds in their enantiomerically pure form with excellent enantiomeric excess (up to 99% ee) was achieved. Furthermore, the synthetic applicability of this methodology was illustrated through the synthesis of two high value compounds, (R)-Pronethalol and (S)-3-hydroxy-N-methyl-3-phenylpropanamide, which is an immediate precursor of bioactive molecules such as (S)-Fluoxetine.

    The second part of this thesis deals with the mechanistic study of the acylative KR catalyzed by the planar-chiral DMAP derivative. Reaction Progress Kinetic Analysis methodology was used in the investigation of the reaction mechanism, probing that no notable product inhibition or decomposition of the catalyst occurs in the studied system. The reaction rate showed fractional order dependence on the concentration of both reactants. Furthermore, NMR spectroscopy was utilized to study the equilibrium between the different catalyst states, which explains the measured kinetics of the reaction.

    List of papers
    1. Non-enzymatic kinetic resolution of 1,2-azidoalcohols using a planar-chiral DMAP derivative catalyst
    Open this publication in new window or tab >>Non-enzymatic kinetic resolution of 1,2-azidoalcohols using a planar-chiral DMAP derivative catalyst
    2013 (English)In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 69, no 2, p. 753-757Article in journal (Refereed) Published
    Abstract [en]

    Optically pure 1,2-azidoalcohols are widely used as precursors for other high value organic products. A non-enzymatic kinetic resolution procedure for the stereoselective synthesis of chiral 1,2-azidoalcohols from the readily available racemic counterparts has been developed, employing a planar-chiral DMAP derivative catalyst. Following this procedure, a range of aromatic 1,2-azidoalcohols was obtained in good selectivities (up to S=45) and high enantiomeric excess (up to 99% ee).

    Keywords
    Non-enzymatic kinetic resolution, 1, 2-Azidoalcohols, Planar-chiral DMAP derivative catalyst, Ferrocenyl catalyst
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-189450 (URN)10.1016/j.tet.2012.10.077 (DOI)000314371800045 ()
    Available from: 2013-01-02 Created: 2013-01-02 Last updated: 2017-12-06Bibliographically approved
    2. Kinetic resolution of 2-hydroxy-2-aryl-ethylphosphonates by a non-enzymatic acylation catalyst
    Open this publication in new window or tab >>Kinetic resolution of 2-hydroxy-2-aryl-ethylphosphonates by a non-enzymatic acylation catalyst
    2014 (English)In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 70, no 24, p. 3807-3811Article in journal (Refereed) Published
    Abstract [en]

    Optically pure hydroxyphosphonates are widely used as derivatizable compounds that can be incorporated into a variety of synthetic strategies for the preparation of other high value organic products. A non-enzymatic kinetic resolution procedure to obtain chiral 2-hydroxy-2-arylethylphosphonates from the easily available racemic counterparts is described. A range of 2-hydroxy-2-arylethylphosphonates was efficiently resolved employing a planar-chiral DMAP derived catalyst with good selectivities (up to S=68). The chiral hydroxyphosphonates were isolated in good yields and high enantiomeric excess (>94% ee).

    Keywords
    Non-enzymatic kinetic resolution, 2-Hydroxy-2-arylethylphosphonates, Planar chiral DMAP derivative catalyst
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-227994 (URN)10.1016/j.tet.2014.03.102 (DOI)000336710200010 ()
    Available from: 2014-07-04 Created: 2014-07-02 Last updated: 2017-12-05Bibliographically approved
    3. Access to optically pure β-hydroxy esters via non-enzymatic kinetic resolution by a planar-chiral DMAP catalyst
    Open this publication in new window or tab >>Access to optically pure β-hydroxy esters via non-enzymatic kinetic resolution by a planar-chiral DMAP catalyst
    2014 (English)In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 19, no 9, p. 14273-14291Article in journal (Refereed) Published
    Abstract [en]

    The development of new approaches to obtain optically pure β-hydroxy esters is an important area in synthetic organic chemistry since they are precursors of other high value compounds. Herein, the kinetic resolution of racemic β-hydroxy esters using a planar-chiral DMAP derivative catalyst is presented. Following this procedure, a range of aromatic β-hydroxy esters was obtained in excellent selectivities (up to = 107) and high enantiomeric excess (up to 99% ee). Furthermore, the utility of the present method was demonstrated in the synthesis of (S)-3-hydroxy-N-methyl-3-phenylpropanamide, a key intermediate for bioactive molecules such as fluoxetine, tomoxetine or nisoxetine, in its enantiomerically pure form.

    Keywords
    non-enzymatic kinetic resolution, β-hydroxy esters, planar-chiral DMAP catalyst, ferrocenyl catalyst
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-224444 (URN)10.3390/molecules190914273 (DOI)000343093100085 ()25215586 (PubMedID)
    Note

    Alba E. DiazIvarez and Laura Mesas-Sanchez contributed equally to this work.

    Available from: 2014-10-08 Created: 2014-05-12 Last updated: 2017-12-05Bibliographically approved
    4. A Mechanistic Investigation of the Kinetic Resolution of Secondary Aromatic Alcohols Using a Ferrocene-Based Planar Chiral 4-(Dimethylamino)pyridine Catalyst
    Open this publication in new window or tab >>A Mechanistic Investigation of the Kinetic Resolution of Secondary Aromatic Alcohols Using a Ferrocene-Based Planar Chiral 4-(Dimethylamino)pyridine Catalyst
    2015 (English)In: CHEMISTRY-A EUROPEAN JOURNAL, ISSN 0947-6539, Vol. 21, no 14, p. 5623-5631Article in journal (Refereed) Published
    Abstract [en]

    A detailed kinetic analysis for the acetylation of 1-phenylethanol with acetic anhydride catalyzed by the planar chiral DMAP catalyst (–)-1 is presented. The study include a computational investigation of the potential energy surface including the rate-limiting and stereoselective transitionstates at the DFT level of theory. The kinetic study suggests that the reaction proceeds with first order in catalyst and in 1-phenylethanol, while the acetic anhydride shows a fractional order. The fractional order is racionalized based on an equilibrium between the free and the acetylated catalyst.

    Keywords
    Reaction progress kinetic analysis, DFT calculation
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-233714 (URN)10.1002/chem.201405793 (DOI)000352504500041 ()25677932 (PubMedID)
    Available from: 2014-10-09 Created: 2014-10-08 Last updated: 2015-05-12Bibliographically approved
  • 22.
    Mesas-Sánchez, Laura
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Dinér, Peter
    KTH Royal Institute of Technology.
    A Mechanistic Investigation of the Kinetic Resolution of Secondary Aromatic Alcohols Using a Ferrocene-Based Planar Chiral 4-(Dimethylamino)pyridine Catalyst2015In: CHEMISTRY-A EUROPEAN JOURNAL, ISSN 0947-6539, Vol. 21, no 14, p. 5623-5631Article in journal (Refereed)
    Abstract [en]

    A detailed kinetic analysis for the acetylation of 1-phenylethanol with acetic anhydride catalyzed by the planar chiral DMAP catalyst (–)-1 is presented. The study include a computational investigation of the potential energy surface including the rate-limiting and stereoselective transitionstates at the DFT level of theory. The kinetic study suggests that the reaction proceeds with first order in catalyst and in 1-phenylethanol, while the acetic anhydride shows a fractional order. The fractional order is racionalized based on an equilibrium between the free and the acetylated catalyst.

  • 23.
    Norrehed, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Modulation of Molecular Properties: Host–Guest Interactions for Structural Analysis and Chemical Reactions2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis concerns the construction, use and modulation of various host–guest systems, from small bispidines for binding of inorganic ions to bisporphyrin clips for supramolecular systems.

    Small flexible molecules undergo fast conformational movements when in solution. These conformational movements generate time-averaged population-weighted chemical shifts, coupling constants and NOEs when analysed by NMR spectroscopy. A bisporphyrin clip was designed to be used as a host for restriction of conformational movements of small flexible molecules by ditopic metal-ligand binding. Based on conformational analysis in combination with NMR analysis of molecular flexibility in solution (NAMFIS), the relative stereochemistry of flexible alditol-derived diamines containing three or four consecutive stereocentres could be determined.

    To further explore the idea of conformational deconvolution via host–guest binding, two flexible molecular tweezers with photoswitchable moieties were developed. Upon photoswitching cis/trans isomerisation facilitates the opening and closing of these bisporphyrin hosts. A guest molecule could then be exposed to a “catch and stretch” or “catch and release” effect. Preliminary studies have shown that photoisomerisation of the constructed systems is possible without photodecomposition and preliminary binding studies have been conducted.

    Controlled modulation of molecular conformations is of interest especially if the conformational steering activates a unit working as a nucleator in a larger structure or facilitates a reaction. The protonation-triggered modulation of bispidine conformations has been investigated. In addition to previously reported conformations we have observed that upon diprotonation a bispidine derivative can be driven into the unusual boat-boat conformation.

    Finally, the unexpected formation of persistent organic radicals with a cyclophane motif from the reaction of N,N´-diphenyl-1-5-diazacyclooctane and AgBF4 is described. Interestingly, these diradicals exhibit features such as intramolecular π-stacking without lateral displacement and also intramolecular spin pairing.

     

    List of papers
    1. Conformational restriction of flexible molecules in solution by a semirigid bis-porphyrin molecular tweezer
    Open this publication in new window or tab >>Conformational restriction of flexible molecules in solution by a semirigid bis-porphyrin molecular tweezer
    Show others...
    2013 (English)In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 69, no 34, p. 7131-7138Article in journal (Refereed) Published
    Abstract [en]

    A semirigid bis-porphyrin molecular clip with a glycoluril backbone has been synthesized. The clip provides an adaptable molecular cavity for binding of diamines. Binding constants for diamines of 104–107 M−1 are orders of magnitude higher than those for monoamines of 103 M−1, indicating a preference to bidentate binding. NMR studies confirmed that binding of bidentate guests occurs inside the clip. Short- and medium-size acyclic molecular guests are locked into a single, extended conformation, and also guests with longer flexible chains exhibit considerably less conformational mobility than when free in solution. The size of the cavity adapts to the guest size, as indicated by modelling studies and self diffusion constants of the complexes.

    Keywords
    Conformational analysis, NMR spectroscopy, Hosteguest systems, Supramolecular chemistry, Porphyrinoids
    National Category
    Natural Sciences Organic Chemistry
    Research subject
    Chemistry with specialization in Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-206036 (URN)10.1016/j.tet.2013.06.013 (DOI)000322098000027 ()
    Funder
    Swedish Research Council
    Available from: 2013-08-26 Created: 2013-08-26 Last updated: 2017-12-06Bibliographically approved
    2. Improved stereochemical analysis of conformationally flexible diamines by binding to a bisporphyrin molecular clip
    Open this publication in new window or tab >>Improved stereochemical analysis of conformationally flexible diamines by binding to a bisporphyrin molecular clip
    2013 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 19, no 43, p. 14631-14638Article in journal (Refereed) Published
    Abstract [en]

    The relative stereochemistry of acyclic diamines with several stereogenic centers has been analyzed by NMR spectroscopy in combination with conformational deconvolution. Binding to a bisporphyrin molecular clip improves the stereochemical assignment significantly. The diamines were synthesized from inexpensive sugar alcohols, and their stable hydrochlorides were quantitatively converted into free bases by treatment with ion-exchange resin.

    Keywords
    configuration determination, conformational analysis, host–guest systems, N ligands, NMR spectroscopy
    National Category
    Natural Sciences Organic Chemistry
    Research subject
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-206040 (URN)10.1002/chem.201300533 (DOI)000330288400025 ()
    Funder
    Swedish Research Council
    Available from: 2013-08-26 Created: 2013-08-26 Last updated: 2017-12-06Bibliographically approved
    3. Photomodulable bis-porphyrin molecular tweezers for conformational studies of diamine guests
    Open this publication in new window or tab >>Photomodulable bis-porphyrin molecular tweezers for conformational studies of diamine guests
    Show others...
    (English)Manuscript (preprint) (Other academic)
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-206039 (URN)
    Available from: 2013-08-26 Created: 2013-08-26 Last updated: 2014-01-23
    4. Protonation-triggered Conformational Modulation of an N,N´‑Dialkylbispidine: First observation of the elusive boat-boat conformer
    Open this publication in new window or tab >>Protonation-triggered Conformational Modulation of an N,N´‑Dialkylbispidine: First observation of the elusive boat-boat conformer
    2013 (English)In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 11, p. 6292-6299Article in journal (Refereed) Published
    Abstract [en]

    Modulation of the solution conformations of N,N′-bis(benzhydryl)bispidine has been achieved by protonation. Conformers have been characterized by NMR spectroscopy using nuclear Overhauser effects and residual dipolar couplings. In contrast to the preference for the chair–chair conformation for the free base and the monoprotonated species, the diprotonated bispidine is revealed to exist as a mixture of chair–boat and boat–boat conformers. While boat–boat conformers of bispidines have previously not been detected, they are here observed to constitute up to 70% of the bispidine population.

    National Category
    Natural Sciences Organic Chemistry
    Research subject
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-206042 (URN)10.1039/c3ob41122b (DOI)000324507100010 ()
    Funder
    Swedish Research Council
    Available from: 2013-08-26 Created: 2013-08-26 Last updated: 2017-12-06Bibliographically approved
    5. Synthesis of persistent organic dication diradicals incorporating a cyclophane motif with intramolecular pi-stacking
    Open this publication in new window or tab >>Synthesis of persistent organic dication diradicals incorporating a cyclophane motif with intramolecular pi-stacking
    Show others...
    (English)Article in journal (Other academic) Submitted
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-206043 (URN)
    Available from: 2013-08-26 Created: 2013-08-26 Last updated: 2014-01-23Bibliographically approved
  • 24.
    Norrehed, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Erdélyi, Maté
    Light, Mark E.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Protonation-triggered Conformational Modulation of an N,N´‑Dialkylbispidine: First observation of the elusive boat-boat conformer2013In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 11, p. 6292-6299Article in journal (Refereed)
    Abstract [en]

    Modulation of the solution conformations of N,N′-bis(benzhydryl)bispidine has been achieved by protonation. Conformers have been characterized by NMR spectroscopy using nuclear Overhauser effects and residual dipolar couplings. In contrast to the preference for the chair–chair conformation for the free base and the monoprotonated species, the diprotonated bispidine is revealed to exist as a mixture of chair–boat and boat–boat conformers. While boat–boat conformers of bispidines have previously not been detected, they are here observed to constitute up to 70% of the bispidine population.

  • 25.
    Norrehed, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Johansson, Henrik
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Improved stereochemical analysis of conformationally flexible diamines by binding to a bisporphyrin molecular clip2013In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 19, no 43, p. 14631-14638Article in journal (Refereed)
    Abstract [en]

    The relative stereochemistry of acyclic diamines with several stereogenic centers has been analyzed by NMR spectroscopy in combination with conformational deconvolution. Binding to a bisporphyrin molecular clip improves the stereochemical assignment significantly. The diamines were synthesized from inexpensive sugar alcohols, and their stable hydrochlorides were quantitatively converted into free bases by treatment with ion-exchange resin.

  • 26.
    Norrehed, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Polavarapu, Prasad
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Yang, Wenzhi
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Conformational restriction of flexible molecules in solution by a semirigid bis-porphyrin molecular tweezer2013In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 69, no 34, p. 7131-7138Article in journal (Refereed)
    Abstract [en]

    A semirigid bis-porphyrin molecular clip with a glycoluril backbone has been synthesized. The clip provides an adaptable molecular cavity for binding of diamines. Binding constants for diamines of 104–107 M−1 are orders of magnitude higher than those for monoamines of 103 M−1, indicating a preference to bidentate binding. NMR studies confirmed that binding of bidentate guests occurs inside the clip. Short- and medium-size acyclic molecular guests are locked into a single, extended conformation, and also guests with longer flexible chains exhibit considerably less conformational mobility than when free in solution. The size of the cavity adapts to the guest size, as indicated by modelling studies and self diffusion constants of the complexes.

  • 27.
    Paptchikhine, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Asymmetric Hydrogenations using N, P - Ligated Iridium Complexes2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The research described in this thesis focuses on the catalytic asymmetric hydrogenation of prochiral olefins using N, P – chelated iridium catalysts. This catalytic system is tolerant to a wide range of substrates and performs better than the well-known ruthenium- and rhodium-catalytic systems for substrates devoid of coordinating groups in proximity of the olefin. Low catalytic loadings (often <1 %) and the high atom efficiency of this reaction make it a synthetically useful method of chiral molecule synthesis. The primary aim of this thesis was to develop new catalysts that rapidly and efficiently hydrogenate a broad range of alkenes asymmetrically. Papers I and II describe the synthesis and evaluation of new, highly efficient, chiral N, P – ligated iridium complexes. These catalysts were obtained in relatively few steps, while leaving open possibilities to modify and fine-tune their structure. Their versatility is ideally suited to both industrial uses and to equip any catalyst box. Paper III deals with a common problem of defluorination of vinylic fluorides during the hydrogenation. The catalyst designed in that work performs well for several substrates giving very low defluorination rates making it a good starting point for further improvements to cover a broader scope of vinyl fluorides. The structures of the catalysts from papers I and III also offers an easy approach to attach the catalyst ligands to a solid support. Paper IV explores hydrogenation of vinyl boronates, which gives synthetically interesting borane compounds with high enantioselectivities. Taking into account the rich chemistry of organic boranes, these compounds are very important. Paper V deals with hydrogenation of diphenylvinylphosphine oxides and vinyl phosphonates, another important classes of substrates that give chiral phosphorous containing compounds of interest in many fields of chemistry: such as medicinal chemistry and organocatalysis. In papers VI and VII we explore the Birch reaction as a source of prochiral olefins. By combining asymmetric hydrogenation with it, we obtain a powerful method to create chiral compounds with excellent enantioselectivities that are next to impossible to make by other routes. The products of the asymmetric hydrogenation are further modified by other well-known transformation to create other induced stereogenic centres.

    List of papers
    1. Development of new thiazole-based iridium catalysts and their applications in the asymmetric hydrogenation of trisubstituted olefins
    Open this publication in new window or tab >>Development of new thiazole-based iridium catalysts and their applications in the asymmetric hydrogenation of trisubstituted olefins
    Show others...
    2008 (English)In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 6, p. 366-373Article in journal (Refereed) Published
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-173458 (URN)
    Available from: 2012-04-24 Created: 2012-04-24 Last updated: 2017-12-07
    2. Bicyclic phosphine-thiazole ligands for the asymmetric hydrogenation of olefins
    Open this publication in new window or tab >>Bicyclic phosphine-thiazole ligands for the asymmetric hydrogenation of olefins
    2010 (English)In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 21, no 11-12, p. 1328-1333Article in journal (Refereed) Published
    Abstract [en]

    New bicyclic thiazole-based chiral N,P-chelating ligands were developed. High activities and enantioselectivities were achieved in the iridium-catalyzed asymmetric hydrogenation of olefins with the new ligands.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-135190 (URN)10.1016/j.tetasy.2010.03.023 (DOI)000281095300002 ()
    Available from: 2010-12-06 Created: 2010-12-06 Last updated: 2017-12-11Bibliographically approved
    3. Iridium-Catalyzed Asymmetric Hydrogenation of Fluorinated Olefins Using N,P-Ligands: A struggle with hydrogenolysis and selectivity
    Open this publication in new window or tab >>Iridium-Catalyzed Asymmetric Hydrogenation of Fluorinated Olefins Using N,P-Ligands: A struggle with hydrogenolysis and selectivity
    2007 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 129, no 15, p. 4536-4537Article in journal (Refereed) Published
    Abstract [en]

    To broaden the substrate scope of asymmetric iridium-catalyzed hydrogenation, fluorine-functionalized olefins were synthesized and hydrogenated with iridium complexes. Preliminary results showed high levels of fluorine elimination together with low selectivity. The loss of vinylic fluorine at first seemed difficult to handle, but further studies revealed that a catalyst with an azanorbornyl scaffold in the ligand gave more promising results. With this in mind, a new ligand was developed. This gave among the best results published to date for fluorine asymmetric hydrogenation, yielding high conversion and very high ee's with very little fluorine elimination. Further increasing the selectivity, the trials also revealed that tetrasubstituted fluorine-containing olefins can be hydrogenated with high ee's, despite that this class of compounds has usually shown low reactivity in this reaction type.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-97352 (URN)10.1021/ja0686763 (DOI)000245739700016 ()17375924 (PubMedID)
    Available from: 2008-05-13 Created: 2008-05-13 Last updated: 2017-12-14Bibliographically approved
    4. Iridium-catalyzed enantioselective hydrogenation of vinyl boronates
    Open this publication in new window or tab >>Iridium-catalyzed enantioselective hydrogenation of vinyl boronates
    2009 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 40, p. 5996-5998Article in journal (Refereed) Published
    Abstract [en]

    The first Ir-catalyzed asymmetric hydrogenations of vinyl boronates have been performed using low catalyst loadings (0.5 mol%) and pressure (as low as 1 bar). Good selectivities (76-98% ee) were obtained for a range of substrates.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-121862 (URN)10.1039/b912590f (DOI)000270542300008 ()19809622 (PubMedID)
    Available from: 2010-03-31 Created: 2010-03-31 Last updated: 2017-12-12Bibliographically approved
    5. Iridium-N,P-ligand-catalyzed enantioselective hydrogenation of diphenylvinylphosphine oxides and vinylphosphonates
    Open this publication in new window or tab >>Iridium-N,P-ligand-catalyzed enantioselective hydrogenation of diphenylvinylphosphine oxides and vinylphosphonates
    2009 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 131, no 23, p. 8285-8289Article in journal (Refereed) Published
    Abstract [en]

    Diphenylvinylphosphine oxides and di- and trisubstituted vinylphosphonates have been employed as substrates in iridium-catalyzed asymmetric hydrogenations. Complete conversions and excellent enantioselectivities (up to and above 99% ee) were observed for a range of substrates with both aromatic and aliphatic groups at the prochiral carbon. We have also hydrogenated electron-deficient carboxyethylvinylphosphonates with excellent stereoselectivity (up to and above 99% ee). The hydrogenated products of both classes of substrates are synthetically useful intermediates.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-121865 (URN)10.1021/ja901437t (DOI)000267623100057 ()19462955 (PubMedID)
    Available from: 2010-03-31 Created: 2010-03-31 Last updated: 2017-12-12Bibliographically approved
    6. Sequential Birch reaction and asymmetric Ir-catalyzed hydrogenation as a route to chiral building blocks
    Open this publication in new window or tab >>Sequential Birch reaction and asymmetric Ir-catalyzed hydrogenation as a route to chiral building blocks
    2011 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 47, no 13, p. 3989-3991Article in journal (Refereed) Published
    Abstract [en]

    A range of 1,2,4-trisubstituted cyclohexadienes obtained from the Birch reaction were hydrogenated asymmetrically to produce synthetically valuable chiral compounds in high enantio- and diastereoselectivity.

    National Category
    Biochemistry and Molecular Biology
    Identifiers
    urn:nbn:se:uu:diva-150770 (URN)10.1039/c0cc05619g (DOI)000288386600089 ()21327284 (PubMedID)
    Available from: 2011-04-06 Created: 2011-04-06 Last updated: 2017-12-11Bibliographically approved
    7. The Birch reaction as a source of substrates for asymmetric hydrogenation
    Open this publication in new window or tab >>The Birch reaction as a source of substrates for asymmetric hydrogenation
    (English)Manuscript (preprint) (Other academic)
    Keywords
    birch reaction, asymmetric hydrogenation, cyclohexanes, 1, 6-diketone
    National Category
    Organic Chemistry
    Research subject
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-173230 (URN)
    Available from: 2012-04-20 Created: 2012-04-20 Last updated: 2012-08-01
  • 28.
    Paptchikhine, Alexander
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Peters, Byron
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Govender, Thavendran
    School of Chemistry, University of KwaZulu-Natal.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    The Birch reaction as a source of substrates for asymmetric hydrogenationManuscript (preprint) (Other academic)
  • 29. Peters, Byron K.
    et al.
    Zhou, Taigang
    Rujirawanich, Janjira
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Cadu, Alban
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Singh, Thishana
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Rabten, Wangchuk
    Kerdphon, Suttichat
    Andersson, Pher G.
    An Enantioselective Approach to the Preparation of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation2014In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 136, no 47, p. 16557-16562Article in journal (Refereed)
    Abstract [en]

    Several chiral sulfonyl compounds were prepared using the iridium catalyzed asymmetric hydrogenation reaction. Vinylic, allylic and homoallylic sulfone substitutions were investigated, and high enantioselectivity is maintained regardless of the location of the olefin with respect to the sulfone. Impressive stereoselectivity was obtained for dialkyl substitutions, which typically are challenging substrates in the hydrogenation. As expected, the more bulky Z-substrates were hydrogenated slower than the corresponding E isomers, and in slightly lower enantioselectivity.

  • 30.
    Poon, Jia-Fei
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Alao, John Patrick
    Sunnerhagen, Per
    Dinér, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Azastilbenes: a cut-off to p38 MAPK inhibitors2013In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 11, no 27, p. 4526-4536Article in journal (Refereed)
    Abstract [en]

    Inhibitors with vicinal 4-fluorophenyl/4-pyridine rings on a five- or six-membered heterocyclic ring are known to inhibit the p38 mitogen-activated protein kinase (MAPK), which is a potential target for rheumatoid arthritis and several different types of cancer. Several substituted azastilbene-based compounds with vicinal 4-fluorophenyl/4-pyridine rings were designed using computational docking, synthesized, and evaluated in a cell-free radiometric p38[small alpha] assay. The biochemical evaluation shows that the best inhibition (down to 110 nM) is achieved for azastilbene-based compounds having an isopropylamine substituent in the 2-position of the pyridine ring. The inhibition of p38 signaling in human breast cancer cells was observed for two of the compounds.

  • 31.
    Rydergren, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Chemical Modifications of Hyaluronan using DMTMM-Activated Amidation2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    An alternative approach to chemically modifying hyaluronan (HA) has been investigated. The triazine derivative 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium (DMTMM) has been used to activate carboxylic groups on HA, which react further to form stable amide bonds with primary and secondary amines. The reaction can either be used to couple monoamines to HA or to produce hydrogels by using diamines that form crosslinks between the HA chains. The reaction between HA and DMTMM has been investigated and optimized in regard to degree of substitution (DS). Analysis using SEC-LC-UV demonstrated that the reaction was successful in coupling benzylamine to HA with a DS of 40%. Gel formation was successful using hexamethylene diamine as a crosslinker. Results also show that the reaction can be controlled by either the DMTMM or the amine concentration so that a specific degree of substitution or crosslinking is achieved. The stability of DMTMM has also been examined, and degradation studies of DMTMM in H2O at 50 °C with 1H NMR analysis show that 11% of the starting material remains after 48 hours. The reaction has proven to be an effective alternative to other modification methods with cheap reagents, simple procedures and the ability to control the amount of modification. Further investigations are nonetheless required in order to determine the full potential the DMTMM-activated amidation of HA.

  • 32.
    Sawadjoon, Supaporn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Palladium-Catalyzed Nucleophilic Substitution of Alcohols: Mechanistic Studies and Synthetic Applications2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis deals with the palladium-catalyzed nucleophilic substitution of π-activated alcohols in which the C–O bond of a non-manipulated hydroxyl group is cleaved. The thesis is divided in two chapters describing two different catalytic systems.

    Chapter 2 describes a heterogeneous palladium-catalyzed transfer hydrogenolysis of primary, secondary, and tertiary benzylic alcohols to generate the corresponding aromatic hydrocarbons using formic acid as the hydrogen donor. A detailed mechanistic investigation of this reaction has been conducted that establish the kinetic order of each reaction component and also the deuterium kinetic isotope effects. This data provide a mechanistic picture that the hydride transfer from formic acid to palladium, and not the C–O bond cleavage, is involved in the rate-determining step and that a catalytic amount of a base promotes the transfer hydrogenolysis.

    Chapter 3 describes the development, mechanistic studies and synthetic scope of a homogeneous palladium-catalyzed amination of allylic alcohols. Isolation of the catalyst precursor and equilibrium studies of the palladium and π-acidic triphenylphosphite ligand show unique properties of this catalytic system. Stereochemical, kinetic, and kinetic isotope studies have been performed to provide insight into the mechanism of C–O bond cleavage of allylic alcohol and C–N bond formation catalyzed by the palladium complex. Interestingly, both O–H and C–O bond cleavages are involved in rate-determining steps.

    List of papers
    1. Pd-Catalyzed Transfer Hydrogenolysis of Primary, Secondary, and Tertiary Benzylic Alcohols by Formic Acid: A Mechanistic Study
    Open this publication in new window or tab >>Pd-Catalyzed Transfer Hydrogenolysis of Primary, Secondary, and Tertiary Benzylic Alcohols by Formic Acid: A Mechanistic Study
    2013 (English)In: ACS Catalysis, ISSN 2155-5435, Vol. 3, no 4, p. 635-642Article in journal (Refereed) Published
    Abstract [en]

    A palladium-catalyzed transfer hydrogenolysis of primary, secondary, and tertiary benzylic alcohols by formic acid has been developed and studied. The product hydrocarbons were obtained in excellent yields from bothsecondary and tertiary benzylic alcohols and in good yields for primary benzylicalcohols. The rate of disappearance of 1-phenylethanol (1) follows zero-order dependence in 1 and first-order dependence in formic acid and palladium. Catalytic amounts of base inhibit a competing disproportionation reaction ofalcohol to alkane and ketone, and an optimum was obtained when 5 equiv ofbase to palladium was used Deuterium kinetic isotope studies for the transferhydrogenolysis reveal individual isotope effects for the hydridic position (k(CHOH)/k(CDOH) = 2.26 +/- 0.24) and the protic position (k(CHOH)/k(CHOD) = 0.62 +/- 0.06) of the formic acid. Simultaneous deuteration in both positions offormic acid gave a combined isotope effect of (k(CHOH)/k(CDOD) = 1.41 +/- 0.11). We propose a mechanism involving the following steps: a competitive inhibition of the open palladium site by adsorption of the formate anion to generate formato-palladium species, followed by a reversible protonation and arate-limiting hydride transfer to obtain the active palladium with chemisorbed hydrogen that performs the hydrogenolysis of the alcohol in a fast reaction step.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-196658 (URN)10.1021/cs300785r (DOI)000317328000024 ()
    Funder
    The Swedish Energy Agency
    Available from: 2013-03-12 Created: 2013-03-12 Last updated: 2014-01-23Bibliographically approved
    2. An atom efficient route to N-aryl and N-alkyl pyrrolines by transition metal catalysis
    Open this publication in new window or tab >>An atom efficient route to N-aryl and N-alkyl pyrrolines by transition metal catalysis
    2011 (English)In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 9, no 7, p. 2548-2554Article in journal (Refereed) Published
    Abstract [en]

    The synthesis of N-aryl, N-tosyl, and N-alkyl pyrrolines from allyl alcohols and amines has been developed. The reaction sequence includes a palladium-catalyzed allylation step in which non-manipulated allyl alcohol is used to generate the diallylated amine in good to excellent yield. An excess of allyl alcohol was necessary for efficient diallylation of the amine, where the excess alcohol could be recycled three times. For aryl and tosyl amines, Pd[P(OPh)(3)](4) was used and for benzyl and alkyl amines a catalytic system comprising Pd(OAc)(2), (PBu3)-Bu-n, and BEt3 was used. Both the electronic properties and the steric influence of the amine affected the efficiency of the allylation. The isolated diallylated amines were transformed into their corresponding pyrrolines by ring-closing metathesis catalyzed by (H(2)IMes)(PCy3)Cl2RuCHPh in good to excellent yield. A one-pot reaction was developed in which aniline was transformed into the corresponding pyrroline without isolating the diallylated intermediate. This one-pot reaction was successfully scaled-up to 1 mL of aniline in which the N-phenyl pyrroline was isolated in 95% yield. The versatility of the reaction in which 3-methyl-1-phenyl pyrroline was prepared in two-steps was demonstrated.

    National Category
    Biochemistry and Molecular Biology
    Identifiers
    urn:nbn:se:uu:diva-150726 (URN)10.1039/c0ob00383b (DOI)000288456700063 ()21344095 (PubMedID)
    Available from: 2011-04-05 Created: 2011-04-05 Last updated: 2017-12-11Bibliographically approved
    3.
    The record could not be found. The reason may be that the record is no longer available or you may have typed in a wrong id in the address field.
    4. Equilibrium Study of Pd(dba)2 and P(OPh)3 in the Pd-Catalyzed Allylation of Aniline by Allyl Alcohol
    Open this publication in new window or tab >>Equilibrium Study of Pd(dba)2 and P(OPh)3 in the Pd-Catalyzed Allylation of Aniline by Allyl Alcohol
    Show others...
    2014 (English)In: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 33, no 1, p. 249-253Article in journal (Refereed) Published
    Abstract [en]

    Reaction of Pd(dba)2 and P(OPh)3 shows a unique equilibrium where the Pd[P(OPh)3]3 complex is favored over both Pd(dba)[P(OPh)3]2 and Pd[P(OPh)3]4 complexes at room temperature. At a lower temperature, Pd[P(OPh)3]4 becomes the most abundant complex in solution. X-ray studies of Pd[P(OPh)3]3 and Pd(dba)[P(OPh)3]2 complexes show that both complexes have a trigonal geometry with a Pd–P distance of 2.25 Å due to the π-acidity of the phosphite ligand. In solution, pure Pd(dba)[P(OPh)3]2 complex equilibrates to the favored Pd[P(OPh)3]3 complex, which is the most stable complex of those studied, and also forms the most active catalytic species. This catalyst precursor dissociates one ligand to give the reactive Pd[P(OPh)3]2, which performs an oxidative addition of nonmanipulated allyl alcohol to generate the π-allyl-Pd[P(OPh)3]2 intermediate according to ESI-MS studies.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-218947 (URN)10.1021/om4009873 (DOI)000329879900029 ()
    Available from: 2014-02-27 Created: 2014-02-20 Last updated: 2017-12-05Bibliographically approved
  • 33.
    Singh, Vijay
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Poon, Jia-fei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Butcher, Ray
    Dpt of Chemistry, Howard University.
    Engman, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Pyridoxine-derived organoselenium compounds with glutathione peroxidase-like and chain-breaking antioxidant activity2014In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, no 39, p. 12563-12571Article in journal (Refereed)
    Abstract [en]

    One of the vitamin B6 vitamers, pyridoxine, wasmodified to incorporate selenium in various oxidation statesin place of the methyl group in position 2. Such compoundswere conveniently accessed by treatment of bis-4,5-(carbo-ethoxy)-2-iodo-3-pyridinol with disodium diselenide andLiAlH4-reduction. After work-up, selone7was isolated ingood yield as an air-stable crystalline material. Hydrogenbonding to the neighboring hydroxyl group, as revealed bythe short intramolecular Se···H distance in the crystal struc-ture is likely to provide extra stabilization to the compound.Computational studies showed that selone7is more stablethan the corresponding selenol tautomer by 12.2 kcalmol1.Hydrogen peroxide oxidation of the selone7afforded di-selenide12, and, on further oxidation, seleninic acid13.Treatment of the seleninic acid with thiophenol provided anisolable selenosulfide14. The glutathione peroxidase-likeproperties of the pyridoxine-derived compounds were as-sessed by using the coupled reductase method. Seleninicacid13was found to be twofold more active than ebselen.The chain-breaking capacity of the pyridoxine compoundswere studied in a water/chlorobenzene membrane modelcontaining linoleic acid as an oxidizable substrate andN-ace-tylcysteine as a thiol reducing agent. Diselenide15couldmatcha-tocopherol when it comes to reactivity towardsperoxyl radicals and inhibition time.

  • 34.
    Tšupova, Svetlana
    et al.
    Ruprecht-Karls-Universität Heidelberg.
    Cadu, Alban
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Stuck, Fabian
    Ruprecht-Karls-Universität Heidelberg.
    Rominger, Frank
    Ruprecht-Karls-Universität Heidelberg.
    Rudolph, Matthias
    Ruprecht-Karls-Universität Heidelberg.
    Samec, Joseph
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry. Stockholm University.
    Hashmi, A. Stephen K.
    Ruprecht-Karls-Universität Heidelberg.
    Dual Gold (I) Catalysed Cyclisation of Dialkynyl Pyridinium saltsManuscript (preprint) (Other academic)
    Abstract [en]

    Novel dialkynyl pyridines were synthesised and protected as alkyl salts for dual gold (I) catalysed cycloisomerisation. Different alkyl groups and counter ions were screened for the salts, with benzyl and PF6- providing the best results. The cyclisation led to NMR yields of >95% being obtained for a number of substrates. Step-wise hydrogenation of products could be carried out in one-pot by Pd/C, with selective reduction of the double bonds, followed by deprotection of the Bn group.

  • 35.
    Verendel, J. Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Transition Metal Catalysis for Selective Synthesis and Sustainable Chemistry2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis discusses the preparation and use of transition-metal catalysts for selective organic chemical reactions. Specifically, two different matters have been studied; the asymmetric hydrogenation of carbon-carbon double bonds using N,P-ligated iridium catalysts and the metal-catalyzed transfer of small molecules from biomass to synthetic intermediates.

    In the first part of this thesis, chiral N,P-ligands were synthesized and evaluated in iridium catalysts for the asymmetric hydrogenation of non- and weakly functionalized alkenes (Papers I & II). The new catalysts were prepared via chiral-pool strategies and exhibited superior properties for the reduction of certain types of alkenes. In particular, some of the catalysts showed excellent activity and selectivity in the enantioselective reduction of terminal alkenes, and the preparation of a modular catalyst library allowed the asymmetric hydrogenation of a wide range of 1,1-disubstituted alkenes with unprecedented efficiency and enantioselectivity (Paper III). Methods for the selective preparation of chiral hetero- and carbocyclic fragments using iridium-catalyzed asymmetric hydrogenation as an enantiodetermining key step were also developed. A range of elusive chiral building blocks that have applications in pharmaceutical and natural-product chemistry could thus be conveniently prepared (Papers IV & V).

    The second part of this thesis deals with the catalytic decomposition of polysaccharides into sugar alcohols and the incorporation of their decomposition products into alkene substrates. Iridium-catalyzed dehydrogenative decarbonylation was found to decompose polyols into CO:H2 mixtures that could be used immediately in the ex situ low-pressure hydroformylation of styrene (Paper VI). The net process was thus the hydroformylation of alkenes with biomass-derived synthesis gas.

    List of papers
    1. Development of pinene-derived N,P ligands and their utility in catalytic asymmetric hydrogenation
    Open this publication in new window or tab >>Development of pinene-derived N,P ligands and their utility in catalytic asymmetric hydrogenation
    2007 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, no 47, p. 5603-5610Article in journal (Refereed) Published
    Abstract [en]

    New diastereomeric N,P-ligands, derived from the natural product (+)--pinene, have been synthesized and evaluated in iridium-catalyzed asymmetric hydrogenation. The ligands are tetrahydroquinoline derivatives synthesized directly from commercially available -pinene utilizing resolution or recrystallization to separate diastereomers. In reduction of a range of different trisubstituted alkenes the catalysts express very different activities ranging from no activity to high activity. One of the catalysts gives good ee values for some substrates.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-12344 (URN)10.1039/b713257n (DOI)000251269100016 ()
    Available from: 2007-12-13 Created: 2007-12-13 Last updated: 2017-12-11Bibliographically approved
    2. Biaryl phosphite-oxazolines from hydroxyl aminoacid derivatives: highly efficient modular ligands for Ir-catalyzed hydrogenation of alkenes
    Open this publication in new window or tab >>Biaryl phosphite-oxazolines from hydroxyl aminoacid derivatives: highly efficient modular ligands for Ir-catalyzed hydrogenation of alkenes
    Show others...
    2008 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 33, p. 3888-3890Article in journal (Refereed) Published
    Abstract [en]

    High enantioselectivities and activities are achieved in the Ir-catalyzed hydrogenation of several unfunctionalized olefins using modular biaryl phosphite-oxazoline ligands from hydroxyl aminoacid derivatives, the presence of a biaryl phosphite group is crucial to this success.

    Keywords
    reduction, hydrogenation, diastereoselective syntheses, enantioselective syntheses (incl. cis/trans-isomerism), polyphenylalkane derivatives, carboxylic acid esters (benzene compounds), alcohols (benzene compounds)
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-17849 (URN)10.1039/b806891g (DOI)000258686400015 ()
    Available from: 2008-09-08 Created: 2008-09-08 Last updated: 2017-12-08Bibliographically approved
    3. Iridium phosphite-oxazoline catalysts for the highly enantioselective hydrogenation of terminal alkenes
    Open this publication in new window or tab >>Iridium phosphite-oxazoline catalysts for the highly enantioselective hydrogenation of terminal alkenes
    Show others...
    2009 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 131, no 34, p. 12344-12353Article in journal (Refereed) Published
    Abstract [en]

    A modular library of readily available phosphite-oxazoline ligands (L1-L16a-f) has been successfully applied for the first time in the Ir-catalyzed asymmetric hydrogenation of a broad range of highly unfunctionalized 1,1,-disubstituted terminal alkenes. Enantioselectivities up to >99% and full conversions were obtained in several 1,1-disubstituted alkenes, including substrate classes that have never been asymmetrically hydrogenated before (i.e., 1,1-heteoraryl-alkyl, 1,1-diaryl, trifluoromethyl, etc.). The results indicated that these catalytic systems have high tolerance to the steric and electronic requirements of the substrate and also to the presence of a neighboring polar group. The asymmetric hydrogenations were also performed using propylene carbonate as solvent, which allowed the Ir catalyst to be reused and maintained the excellent enantioselectivities.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-121863 (URN)10.1021/ja904152r (DOI)000269379600068 ()19658416 (PubMedID)
    Available from: 2010-03-31 Created: 2010-03-31 Last updated: 2017-12-12Bibliographically approved
    4. Highly Flexible Synthesis of Chiral Azacycles via Iridium-Catalyzed Hydrogenation
    Open this publication in new window or tab >>Highly Flexible Synthesis of Chiral Azacycles via Iridium-Catalyzed Hydrogenation
    Show others...
    2010 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, no 26, p. 8880-8881Article in journal (Refereed) Published
    Abstract [en]

    A range of saturated chiral azacycles has been prepared in high yield and with high selectivity from simple starting materials. A modular approach with ring-closing metathesis as a key step was used to produce a number of five-, six-, and seven-membered cyclic alkenes. Asymmetric hydrogenation catalyzed by N,P-ligated iridium complexes gave saturated azacycles in high optical purity. This methodology was demonstrated in the synthesis of a pharmaceutical precursor.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-135809 (URN)10.1021/ja103901e (DOI)000279561200033 ()20557052 (PubMedID)
    Available from: 2010-12-09 Created: 2010-12-08 Last updated: 2017-12-11Bibliographically approved
    5. Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
    Open this publication in new window or tab >>Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
    Show others...
    2012 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 21, p. 6507-6513Article in journal (Refereed) Published
    Abstract [en]

    Several types of chiral hetero- and carbocyclic compounds have been synthesized by using the asymmetric hydrogenation of cyclic alkenes. N,P-Ligated iridium catalysts reduced six-membered cyclic alkenes with various substituents and heterofunctionality in good to excellent enantioselectivity, whereas the reduction of five-membered cyclic alkenes was generally less selective, giving modest enantiomeric excesses. The stereoselectivity of the hydrogenation depended more strongly on the substrate structure for the five- rather than the six-membered cyclic alkenes. The major enantiomer formed in the reduction of six-membered alkenes could be predicted from a selectivity model and isomeric alkenes had complementary enantioselectivity, giving opposite optical isomers upon hydrogenation. The utility of the reaction was demonstrated by using it as a key step in the preparation of chiral 1,3-cis-cyclohexane carboxylates.

    Keywords
    asymmetric synthesis, heterocyclic compounds, homogeneous catalysis, hydrogenation, iridium
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-175620 (URN)10.1002/chem.201104073 (DOI)000304045000016 ()
    Available from: 2012-06-12 Created: 2012-06-11 Last updated: 2017-12-07Bibliographically approved
    6. Selective, metal-catalyzed transfer of H2 and CO from polyols to alkenes
    Open this publication in new window or tab >>Selective, metal-catalyzed transfer of H2 and CO from polyols to alkenes
    2013 (English)In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 6, no 3, p. 426-429Article in journal (Refereed) Published
    Keywords
    catalysis, transition metals, renewable feedstocks
    National Category
    Organic Chemistry
    Research subject
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-182817 (URN)10.1002/cssc.201200843 (DOI)000315715400008 ()
    Available from: 2012-10-15 Created: 2012-10-15 Last updated: 2017-12-07Bibliographically approved
  • 36.
    Verendel, J. Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Nordlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Pher G.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Selective, metal-catalyzed transfer of H2 and CO from polyols to alkenes2013In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 6, no 3, p. 426-429Article in journal (Refereed)
  • 37.
    Zhou, Taigang
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Asymmetric Hydrogenation of Functionalized Olefins Using N,P-Ligated Iridium Complexes2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Transition-metal-catalyzed asymmetric hydrogenation is one of the most efficient, straightforward, and well-established methods for preparing enantiomerically enriched compounds. Over the past decades, significant progress has been made with iridium, rhodium and ruthenium complexes to asymmetric hydrogenate a selection of olefins, such as, α,β-unsaturated carboxylic acid derivatives, ketones, imines and phosphonates. Although these metals have been applied successfully in the hydrogenation of olefins, they differ in their substrate tolerance.  Ruthenium and rhodium based catalysts require a coordinating group in the vicinity of the C=C bond. However, iridium based catalysts do not require this coordinating group, hence, asymmetric hydrogenation with iridium catalysts has been widely used for both functionalized and unfunctionalized olefin substrates. This thesis focuses on expanding the substrate scope for asymmetric hydrogenation using chiral N,P-ligated iridium catalysts. Papers I and II investigate the asymmetric hydrogenation of prochiral N-heterocyclic compounds prepared by ring-closing metathesis using the iridium catalysts developed in our group.  These substrates are interesting as they bear resemblance to pharmaceutically active compounds and therefore have tremendous value in medicinal chemistry.  Excellent enantioselectivities, up to >99% ee and conversions were obtained. In papers III and IV we synthesized many unsaturated acyclic and cyclic sulfones with varying substitution patterns.  The sulfones were subjected to hydrogenation using our N,P-ligated iridium catalysts, producing the chiral sulfone products in high enantiomeric excess (up to 99% ee). This methodology was combined with the Ramberg-Bäcklund reaction, offering a novel route to chiral allylic and homoallylic compounds. In addition to obtaining these chiral compounds in good yields, no decrease in enantiomeric excess was observed after the Ramberg-Bäcklund reaction. This strategy has been applied in the preparation of the chiral building block for renin inhibitors.

    List of papers
    1. Highly Flexible Synthesis of Chiral Azacycles via Iridium-Catalyzed Hydrogenation
    Open this publication in new window or tab >>Highly Flexible Synthesis of Chiral Azacycles via Iridium-Catalyzed Hydrogenation
    Show others...
    2010 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, no 26, p. 8880-8881Article in journal (Refereed) Published
    Abstract [en]

    A range of saturated chiral azacycles has been prepared in high yield and with high selectivity from simple starting materials. A modular approach with ring-closing metathesis as a key step was used to produce a number of five-, six-, and seven-membered cyclic alkenes. Asymmetric hydrogenation catalyzed by N,P-ligated iridium complexes gave saturated azacycles in high optical purity. This methodology was demonstrated in the synthesis of a pharmaceutical precursor.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-135809 (URN)10.1021/ja103901e (DOI)000279561200033 ()20557052 (PubMedID)
    Available from: 2010-12-09 Created: 2010-12-08 Last updated: 2017-12-11Bibliographically approved
    2. Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
    Open this publication in new window or tab >>Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
    Show others...
    2012 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 21, p. 6507-6513Article in journal (Refereed) Published
    Abstract [en]

    Several types of chiral hetero- and carbocyclic compounds have been synthesized by using the asymmetric hydrogenation of cyclic alkenes. N,P-Ligated iridium catalysts reduced six-membered cyclic alkenes with various substituents and heterofunctionality in good to excellent enantioselectivity, whereas the reduction of five-membered cyclic alkenes was generally less selective, giving modest enantiomeric excesses. The stereoselectivity of the hydrogenation depended more strongly on the substrate structure for the five- rather than the six-membered cyclic alkenes. The major enantiomer formed in the reduction of six-membered alkenes could be predicted from a selectivity model and isomeric alkenes had complementary enantioselectivity, giving opposite optical isomers upon hydrogenation. The utility of the reaction was demonstrated by using it as a key step in the preparation of chiral 1,3-cis-cyclohexane carboxylates.

    Keywords
    asymmetric synthesis, heterocyclic compounds, homogeneous catalysis, hydrogenation, iridium
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-175620 (URN)10.1002/chem.201104073 (DOI)000304045000016 ()
    Available from: 2012-06-12 Created: 2012-06-11 Last updated: 2017-12-07Bibliographically approved
    3. Enantioselective Synthesis of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation: A Facile Approach to the Preparation of Chiral Allylic and Homoallylic Compounds
    Open this publication in new window or tab >>Enantioselective Synthesis of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation: A Facile Approach to the Preparation of Chiral Allylic and Homoallylic Compounds
    Show others...
    2012 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 134, no 33, p. 13592-13595Article in journal (Refereed) Published
    Abstract [en]

    A highly efficient and enantioselective Ir-catalyzed hydrogenation of unsaturated sulfones was developed. Chiral cyclic and acyclic sulfones were produced in excellent enantioselectivities (up to 98% ee). Coupled with the Ramberg-Backlund rearrangement, this reaction offers a novel route to chiral allylic and homoallylic compounds in excellent enantioselectivities (up to 97% ee) and high yields (up to 94%).

    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-182640 (URN)10.1021/ja306731u (DOI)000307699000016 ()
    Available from: 2012-10-14 Created: 2012-10-14 Last updated: 2017-12-07Bibliographically approved
    4. High Enantioselectivity of Chiral Sulfones byIridium Catalyzed Asymmetric Hydrogenation: An Efficient Access for Total Synthesis of Imperanene
    Open this publication in new window or tab >>High Enantioselectivity of Chiral Sulfones byIridium Catalyzed Asymmetric Hydrogenation: An Efficient Access for Total Synthesis of Imperanene
    (English)Manuscript (preprint) (Other academic)
    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-182643 (URN)
    Available from: 2012-10-14 Created: 2012-10-14 Last updated: 2012-11-12
  • 38.
    Zhou, Taigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Peters, Byron
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Cadu, Alban
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    High Enantioselectivity of Chiral Sulfones byIridium Catalyzed Asymmetric Hydrogenation: An Efficient Access for Total Synthesis of ImperaneneManuscript (preprint) (Other academic)
  • 39.
    Zhou, Taigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Peters, Byron
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Maldonado, Matias
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Govender, Thavendran
    Department of Pharmacy, University of KwaZulu-Natal.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Enantioselective Synthesis of Chiral Sulfones by Ir-Catalyzed Asymmetric Hydrogenation: A Facile Approach to the Preparation of Chiral Allylic and Homoallylic Compounds2012In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 134, no 33, p. 13592-13595Article in journal (Refereed)
    Abstract [en]

    A highly efficient and enantioselective Ir-catalyzed hydrogenation of unsaturated sulfones was developed. Chiral cyclic and acyclic sulfones were produced in excellent enantioselectivities (up to 98% ee). Coupled with the Ramberg-Backlund rearrangement, this reaction offers a novel route to chiral allylic and homoallylic compounds in excellent enantioselectivities (up to 97% ee) and high yields (up to 94%).

1 - 39 of 39
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